Static eliminator



June 9, 1931. F. R. MONROE ET AL 1,809,789

STATIC ELIMINATOR Filed Fb. 12, 1930 9E Il Patented June 9, 1931 UNITED; STAT/Es PATENT oFFicE FRED R. MONROE,'HAROL1) K. DOLSON,.AND BAYARD T. TUTTLE, MIDD'LETOWN,

' \NEW YORK stremo Yntrivirivn'ron,

Application filed February 12, 1930. Serial No. 427,689.

y This invention relates to a novel and im'` prove-drmeans for eliminating static from radio receiving speakers, and the knovel features of the invention will be best understood from the following description and the an* neXed drawings, in which we have shown a selected apparatus embodying the invention and in which: Y y

Fig. 1 is a diagram illustrating the relation of the invention to the receiving set and speaker. Y I

Fig. 2 is an elevat-ion of a set of elimina'- tors used in this embodimentand shown in plan in Fig. 1. c Y Y l Fig.- 3 is a vertical section through one of the eliminators, taken at'riglit angles to the plane ofFig. 2. V f

Referringiirst to F ig. l, we have shown at 1 a receiving set which may be of any suitable form, and as the details do not form any part of this invention we have omitted showing such details. 'The receiving set may be used in connection with a speaker 2, which also may be of any suitable form.' VThe details of this speaker are also immaterial so far as this' invention is concerned and, therefore, such details have been omitted.

It is to be understood that the set `lk and speaker 2 may be incorporated together in a suitablejcabinet, or may -be otherwise arrangedv as desired. In the illustrated embodiment, the speaker is one of the type operated by power, and is provided with conductors 3 connecting it to the receiving set, these conductorsbeing those Which transmit from the receiving set to the speaker the impulses causing the reproduction of sound in the speaker. The lspeaker is also connected to the receiving setby other conductors 4 4o which transmit from the setto the speaker the necessary power to operate the speaker. While we have shown the speaker as being ofthe power operated type, the inventionis equally applicable to a speaker which is not of this type. f

Disposed in'each of the connections formed bythe conductors 3 and L'is an eliminator 5 best shown in'Figs. 2 and 3. V'These elimina tors may be mounted `together on a base ,and this base may be incorporated in a cabinetif a cabinet is used. The eliminators are all of similar construction and a description oflone will serve for all,

VAs best shown in Fig. 3, the eliminator comprises a tube 6i closed at the bottom with a metallic plug 7 and at the top with a second metallic plug 8, it being understood that the tube is of insulating material. Disposed in thebottom of the tube is a carrier which may be absorbent cotton or similar substance, and which is indicated at 9. Resting on top of this carrier is a metallic plate 10. The plug and plate lO'together forni the oppositey boundaries of a space occupied Vby the carrier 9, and the extent of this space may be varied by means ofan' adjusting screw 11 threaded into the plug 8 and having at its lower end a follower 12'adapted to compress a spring 13 against the plate 10. LSuitable terminals 14 and 15 are provided having electrical connections to the plugs 7 and 8 respectively.

The carrier 9 is used as a support for a fine metallic powder, preferably the carrier being saturated with oil before the powder is placed thereon, whereby a film of oil will surround -particles of the powder.y This powder is preferably made in the following manner rlhe first step is'to mi'X together iron, silver, mercury and sulphuric acid, in the proportions of one part of iron, two of mercury and twoof silver, with enough chemically pure `sulphuric acid to complete the reaction and form a sulphate of the mixture of metal. Preferably, theiron is in the form of FeOg; the silver in the form of silver nitrate, and the mercury inthe form of mercury'bichloride.

r After the reactionrhas taken place, the residue is evaporated to dryness, using heat, if necessary, and then the dry residue isreduced to a fine powder, magnetized by passing an electric current therethrough, and mixed with two parts of powdered lodestone, 1/2 lpart of powdered bakelite, and a trace of powdered nickel. Y l

In preparing the powder, it is essential that the han-ds of the worker should not touch the powder,

The next step is to take a Small amount of absorbent cotton, for example, about the size of a pea, care here also being taken not to touch the cotton with the hands. A drop or two of oil of cade or oil of juniper tar is then placed upon the cotton which is permitted to dry, after which the cotton may be dipped into the powder and the last particles shaken ofi'. The cott-on may be then placed in the eliminator, as shown in Fig. 3.

We have found that by using an eliminator in each of the connections between a receiving set and a speaker, each eliminator containing a metallic powder of the kind described above, static, and also to a large eX- tent other noises, are eliminated. So far as we now know, this elimination is caused by providing in each electrical connection from the set to the speaker, a resistance', in the form of a large number of metallic particles, these particles being insulated from each other to a large extent by a film of oil on each particle, and also to some extent by air spaces therebetween.

Furthermore, the bakelite, which is an eX- ample of an insulating material, forms a ground which appears to check the static. The iron, mercury and lodestone appear to form the conductors, the lodestone, in particular, providing for large volume, while the bakelite seems to eliminate the static and the silver and nickel appear to clear the resulting sound. The lodestone also furnishes a permanent magnetic metal, and the other metallic substances are not only previously maguetized but are kept magnetized by the passage of electricity therethrough. The amount of separation of particles may be varied by adjustment of the screw 11. In actual practice, we have found the results of using eliminators constructed as above described, to be very eiiicient in the elimination of static and other noises.

1. In combination, a radio receiving set, a speaker and electrical connections between the set and speaker, said connections having each interposed therein a static eliminator, said eliminator comprising conducting members spaced from each other, with the space therebetween containing a metallic powder with the particles forming it widely distributed throughout said space.

2. In combination, a radio receiving set, a speaker and electrical connections between the set and speaker, said connections having each interposed therein a static eliminator, said eliminator comprising conducting members spaced from each other, with the space therebetween containing a metallic powder with the particles forming it widely distributed throughout said space and with the particles magnetized.

3. In combination, a radio receiving set, a speaker and electrical connections between the set and speaker, said connections having each interposed therein a static eliminator, said eliminator comprising conducting members spaced from each other, with the space therebetween containing a metallic powder with the particles forming it widely distributed throughout said space, and means -for exerting pressure upon said powder.

4. In combination, a radio receiving set, a speaker and electrical connections between the set and speaker, said connections having each interposed therein a static eliminator, said eliminator comprising conducting members spaced from each other, with the space therebetween containing a metallic powder with the particles forming it widely distributed throughout said space, means for exerting pressure upon said powder, and means for varying the amount of said pressure.

5. In combination, a radio receiving set, a speaker and electrical connections between the set and speaker, said connections having each interposed therein a static eliminator, said eliminator comprising conductng members spaced from each other, with the space therebetween containing a metallic powder with the particles forming it widely distributed throughout said space and insulated from each other.

6. In combination, a radio receiving set, a speaker and electrical connections between the set and speaker, said connections having each interposed therein a static eliminator, said eliminator comprising conducting members spaced from each other, with the space therebetween containing a metallic powder with the particles forming it widely distributed throughout said space and insulated from each other, and means for varying the amount of said insulation.

7. In combination, a radio receiving set, a speaker and electrical connections between the set and speaker, said connections having each interposed therein a static eliminator, said eliminator comprising conducting members spaced from each other, with the space therebetween containing a metallic powder with the particles forming it widely distributed throughout said space, said powder including particles of lodestone.

8. In combination, a radio receiving set, a speaker and electrical connections between the set and speaker, said connections having each interposed therein a static eliminator, said eliminator comprising conducting members spaced from each other, with the space therebetween containing a metallic powder with the particles forming it widely distributed throughout said space, said powder including iron and mercury.

9. In combination, a radio receiving set, a speaker and electrical connections between the set and speaker, said connections having each interposed therein a static eliminator, said eliminator comprising conducting members spaced from each other, with thespace therebetween containing a metallic powder with the particles forming it widely diss tributed throughout said space, said powder including iron and mercury and an insulating substance.

10. In combination, a radio receiving set, a speaker and electrical connections between 'the set and speaker, said connections having each interposed therein a static eliminator, said eliminator comprising conducting members spaced from each other, with the space therebetween containing a metallick powder with the particles forming it widely distributed throughout said space, said powder including iron and mercury, together with nickel and silver.

' 11. In combination, a radio receiving set,

a-speaker andelectrical connections between the set and speaker, said connections having each 4interposed therein a static eliminator, said eliminator comprising conducting niembers spaced from each other, with thek space therebetween containing a metallic powder with the particles forming it widely distributed throughout said space, said powder including a compound of iron, silver and mercury.

12. In combination, a radio receiving set, a speaker and electrical connections between the set and speaker, said connections having each interposed therein a static eliminator, said eliminator comprising conducting members spaced from each other, with the space therebetween containing a metallic powder with the particles forming it widelyV distributed throughout said space, said powder including a. compound of iron, silver and mercury, with sulphuric acid.

13. In combination, a radio receiving set, a speaker and electrical connections between the set and speaker, said connections having each interposeditherein a static eliminator, said eliminator comprising conducting members spaced from each other, with the space therebetween containing a metallic powder with the particles forming it widely distributed throughout said space, said powder including a compound of iron, silver and Inercury, with sulphuric acid, mixed with lodestone.

14. In combination, a radio receiving set, a speaker and electrical connections between the set and speaker, said connections having each interposed therein a static eliminator, said eliminator comprising conducting inembers spaced from each other, with the space therebetween containing a metallic powder with 'the particles forming it widely distributed throughout said space, said powder including a compound of iron, silver and mercury, with sulphuric acid, mixed with lode-` stone, and an insulating material.

15. In combination, a radio receiving set, a speaker and electrical connections between the set and speaker, said connections having each interposed therein a static eliminator,

said eliminator comprising conducting members spaced from each other, with the space therebetween containing a metallic powder with the particles forming it widely distributed'throughout said space, said powder ink16. In combination, a radio receiving set,

a speaker and electrical connections between the set and speaker, said connections having each in'terposedtherein a static eliminator, saidreliminator comprising conducting inembers spaced from each other, with the space therebetween containing a metallic powder with the particles forming it widely distribu'ted throughout said space, said powder includinga compound of iron, silver and mercury, with sulphuric acid, mixed with lodestone, an insulatingmaterial, and nickel.

17. In combination, a radio receiving set,

a speaker and electrical connections between the set andjspeaker, said connections having each interposed therein a static eliminator, said eleminator comprising conducting menibers spaced from each other, with the space therebetween containing a metallic powder with the particles forming it widely distributed throughout said space, said powder including a metallic sulphate.

FRED R. MONROE.

HAROLD K. DOLSON.

BAYARD T. TUTTLE.

iic 

